Uni-directional cord take-up device

ABSTRACT

The invention is a dual reel cord take-up device for flat wire cable which as a generally semi-cylindrical upper and lower case half which snap  attach together over a dual-purpose shaft to make two compartments. The first compartment is a cord extension and take-up compartment which is divided in two by a slotted disk on the dual-purpose shaft in that compartment. Flat wire cable is wound on the dual-purpose shaft in both compartments, and extends through two apertures in the walls of the compartment. The cable in one aperture is fixed so it does not move in and out of the aperture. The wire cable in the second aperture is free to extend or retract through the aperture. A spring provides the power to retract cable into the take-up device.

This application is a continuation-in-part of application Ser. No.08/600,406, filed Feb. 12, 1996, now U.S. Pat. No. 5,655,726 forUNI-DIRECTIONAL CORD TAKE-UP DEVICE.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to take-up devices for electricalcords, and more particularly to those take-up devices for flat wirecables used in telephone communication and data transmissions.

2. Background

U.S. Pat. No. 5,230,481 (Wheeler et al.) discloses a dual reel cordtake-up device for connecting a telephone and a cooperating handset.This device serves to connect the handset of a telephone to the body ofthe telephone with a device wherein the connecting cord is wound on aspool. This allows the user of the telephone to pick up the handset,move many feet away from the telephone, and still be connected by cableto the telephone body. Phone cable extends from both sides of the cordtake-up device as the handset is moved away from the phone, and is woundback into both sides of the take-up device as the handset approaches thecradle. When the user returns the handset to the telephone, there is nopile of twisted and coiled extension cord. Instead, all of the phonecable is neatly wound back onto the dual-purpose shaft of the take-updevice.

A feature of this system is that when the user of the handset returnsthe handset to its cradle, the dual-purpose shaft winds up the availablecord. Just before the handset is placed on the cradle, the take-up reel,with its now much shortened external cable link, can contact the desk ortable on which the telephone is situated. This contact can produce anaudible clicking sound which the person on the other end of thetelephone can hear.

There is a need to invent a device for feeding out electrical cablebetween a telephone and its handset, and for taking that cable up into aneat package, without having the take-up device be free floating betweenits attached ends, and without having the possibility of creating noiseas the take-up device contacts objects during retraction and use.

DISCLOSURE OF INVENTION

What we have invented is a cord take-up device for flat wire phone cablewhich feeds out or takes up cable at only one of its two cable entryports.

It includes a generally semi-cylindrical upper case half with twoparallel compartments in a direction perpendicular to the axis of thecylinder, the first compartment being adapted to receive the first endof a dual-purpose dual-purpose shaft, and the second compartment beingadapted to receive the second end of the dual-purpose dual-purpose shaftand a spring cup. The upper case half has snap-fit means for receiving alower case half and means for receiving a flat wire cable.

Also provided is a generally semi-cylindrical lower case half, also withtwo compartments which correspond to the first and second compartmentsof the upper case half. The lower case half also has snap-fit means forreceiving and cooperating with said upper case half snap-fit means. Thelower case half has means for receiving a flat wire cable and has asecond compartment with means for holding the spring cup in the secondcompartment against rotation in one direction but not the other.

Another feature of the invention is a dual-purpose shaft supported andheld in rotatable relationship by both the upper and lower case halves.The dual-purpose shaft is provided on its first end in the firstcompartment of the upper and lower case halves with a slotted disk whichdivides the first end of the dual-purpose shaft into two adjacentchambers for receiving flat wire cable.

The flat wire cable extends through two apertures, with one cable endfixed in an aperture and the other cable end free to extend and retractthrough the other aperture.

The dual-purpose shaft has on its second end in the second compartmentof the upper and lower case halves, a slot in the dual-purpose shaft forreceiving a spring within the spring cup.

The device also contains a generally cylindrical spring cup within thesecond compartment of the upper and lower case halves, the spring cuphaving an outer surface perpendicular to its axis of rotation, meanscooperating with the holding means to hold the cup against rotationrelative to the upper and lower case halves in one direction but not inthe other direction, and spring stop means on its inner cylindricalsurface for foxing one end of the spring to the spring cup.

The device also contains a flat coil spring within the spring cup, thespring being fixed on its outer end to the spring cup and being fixed onits inner and end to the second end of the dual-purpose shaft.

Another feature of our invention is the inclusion of notches within thesecond compartment. These notches interact with the cooperating means ofthe spring cup, which are resilient prongs on its outer cylindricalsurface.

Another feature of our invention is that the spring cup has detent meanson its outer surface perpendicular to its axis of rotation for windingthe spring.

Another feature of our invention is that the apertures in the lower casehalf are sufficiently large to permit the passage of flat wire cable inand out of the device, but are not large enough to permit the passage ofa fold in the flat wire cable.

Another feature of our device is that the dual purpose shaft has alarger diameter in the cable extension and take-out reel than thediameter of the dual purpose shaft in the captive cable reel.

From the practice of our invention an improved phone cord take-up deviceis provided, wherein the device remains stationary in relationship tothe telephone, and cable moves in and out of only one aperture of thedevice.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the telephone equipped with a uni-directionaldual reel cord take-up device.

FIG. 2 is a perspective view of our improved cord take-up device.

FIG. 3 is a cross-sectional view along line 3—3 in FIG. 2.

FIG. 4 is an exploded, partly cross-sectional side view of our improvedcord take-up device.

FIG. 5 is a perspective view of the disk which mounts on thedual-purpose shaft.

FIG. 6 is a side, outside view of the spring cup of our improved cordtake-up device.

FIG. 7 is a cross-sectional view of compartment 30 looking toward secondend 40.

FIG. 8 is a cross-sectional view of compartment 28 looking toward firstend 38.

FIG. 9 is a cross-sectional view of compartment 30 looking toward secondend 40.

FIG. 10 is a cross-sectional view of compartment 28 looking toward firstend 38.

BEST MODE FOR CARRYING OUT INVENTION

Referring to the FIG. 1, there is depicted generally one embodiment ofour improved uni-directional cord take-up device 10. When the phonehandset 18 is removed from the phone 16, as shown in dotted lines, thedevice 10 stays attached to the phone 16. As shown in FIGS. 2, 3 and 4,generally semi-cylindrical upper case half 20 and lower case half 22snapfitcome together to form two parallel compartments, first compartment 36and second compartment 26 inside take-up device 10. The two compartmentsare parallel in a direction perpendicular to the axis of the cylinderwhich the upper and lower case halves create. First compartment 36 isadapted to receive and support in rotatable relationship first end 38 ofdual-purpose shaft 24. Likewise, second compartment 26 is adapted toreceive and support in rotatable relationship second end 40 ofdual-purpose shaft 24, as shown in FIG. 3.

Upper and lower case halves 20 and 22 both have cooperating snap-fitmeans 42 and 42′ for receiving and cooperating with one another forretaining said upper and lower case halves in fixed mutual relationship,as shown in FIG. 4. Also, lower case half has means for receiving flatwire cable, apertures 44 and 44′, in the walls of the lower case half22, or otherwise in the walls of the cord take-up compartments.

First end 38 of dual-purpose shaft 24 has a slotted disk 34 whichdivides the first compartment 36 into two adjacent compartments, 30 and28, which we will call sides A and B, respectively, as shown in FIG. 3.In compartment 28 (Side B) is the captive, cable reel, and the flat wirecable 14 is wound or unwound by wrapping around, or unwrapping from,dual purpose dual-purpose shaft 24. Cable from compartment 28 (side B)extends a short distance outside of the case of device 10 and attachesto strain relief 19, phone jack 12, and the telephone 16. The case canbe attached to the telephone so it is firmly anchored when in use. Thecable which is wrapped around dual-purpose shaft 24 in compartment 28(side B) never leaves the device 10, except for a short extension whichconnects to the phone 16.

FIG. 5 shows slotted disk 34, with hub 35 and slot 66 shown. Slot 66 isfor the passage of flat wire cable.

FIG. 6 shows the spring cup 32, with cooperating means 52 which areresilient prongs. It has an outer surface 50 with detents 58, 60, 62,and 64.

The adjacent compartment 30 (side A) is the cable extension reel andcontains flat wire cable 14 which extends outside of the reel case andattaches to the strain relief 19, phone jack 12, and handset 18. Whenthe user picks up the handset 18 and brings it to his ear, or moves thehandset 18 away from the phone 16, flat wire cable 14 from compartment30 (side A) is dispensed from the dual-purpose shaft 24 through aperture44. This is shown in FIGS. 7 and 9, which are cross-sectional view ofcompartment 30 (side A), looking from the second end 40first end38toward the first end 38second end 40of dual-purpose shaft 24. FIG. 8shows the device 10 with the cable of compartment 28 (side B) when thecable of compartment 30 (side A) is fully retracted within the deviceand wrapped around dual-purpose shaft 24. FIG. 10 shows the cable incompartment 28 (side B) when the cable from compartment 30 (side A) isfully extended outside the compartment 30 (side A) and wound off ofdual-purpose shaft 24.

Dual-purpose shaft 24 is connected to flat coil springs 48 at slot 46.Flat coil spring 48 is housed in compartment 26 of device 10.

Flat coil spring 48 is of a type of spring known as a constant forcespring or a negator spring. A negator spring is best understood when itis compared to a power spring. A power spring is a flat coil springwhich at rest forms a uniform spiral with many turns being evenly spacedfrom the center to the outside of the spring. An example of a powerspring is the spring which is used in watches. Due to the shape of apower spring, more and more torque is required to wind successive layersaround the center shaft. As most of the spring has become wound on tothe center shaft, the last few coils require significantly more force towind on to the center shaft.

A negator spring, by comparison, is actually a power spring which iswound backwards. The result of this is that a negator spring, when itrests, presses against its container, and its coils are as far from thecenter hub as they are allowed to go. The result of this design is thatas the center shaft rotates and pulls coils of the spring from theoutside to wrap around the center shaft, it takes about as much torqueto pull one coil in as it does to pull later coils. Although this torquemay not be completely constant, it is reasonably constant, and much moreconstant than the torque variations of a power spring. The use of anegator spring in this device is significant because it allows thetorque applied by the flat coil spring 48 to be fairly constant nomatter how much flat wire cable 14 is extended from the spring. Thisuniform torque on the flat wire cable 14 significantly improves its lifespan, by not over-stressing this delicate cable.

As flat wire cable 14 is extended from compartment 30, it causesdual-purpose shaft 24 to rotate, which in turn causes flat coil spring48 to be wound onto dual-purpose shaft 24. Flat coil spring 48 is sizedso that when the spring is fully wound on to dual-purpose shaft 24,several turns of flat wire cable 14 remain around dual-purpose shaft 24in compartment 30 (side A) as shown in FIG. 9 and the flat wire cable incompartment 28 (side B) is pressed against the outside of compartment 28but has not begun to reverse wrap around dual-purpose shaft 24, as shownin FIG. 10.

An important feature of the design of this device is that when the cablein compartment 30 (side A) is fully extended, the flat wire cable incompartment 28 (side B) extends out from dual-purpose shaft 24 at notmore than a 90 degree angle. If dual-purpose shaft 24 were allowed torotate clockwise even one half of a revolution further, a loop woulddevelop in the flat wire cable adjacent to dual-purpose shaft 24. Thisloop is shown in FIG. 10 as a dotted dashed line. Formation of this loopcauses a reverse flexing of the flat wire cable 14 and leads topremature failure of the cable. The relationship between the revolutionsallowed by the spring 48, the thickness of the flat wire cable 19 14,and the diameter of dual-purpose shaft 24 in compartment 30 andcompartment 28 is carefully controlled to prevent the formation of thisloop.

As flat wire cable 14 is retracted into the device 10, the oppositesequence of events occurs. As the handset 18 is returned to thetelephone 16, the flat wire cable 14 which is connected to it is reeledon to the dual-purpose shaft 24 in compartment 30 (Side A), and therotation of the dual-purpose shaft 24 causes the flat wire cable 14 incompartment 28 (Side B) to rewind onto dual-purpose shaft 24.

Apertures 44 and 44′ are constructed to be large enough to allow thepassage of flat wire cable through the apertures, but are not largeenough to allow the passage of folded or kinked flat wire cable. In thisway, a kink or twist in the cable is not allowed to pass through theaperture 44 or 44 ¹ 44′ and be wound onto the dual-purpose shaft 24.Further, and as illustrated, the apertures 44, 44′ may be positioned onthe lowercase half 22, or otherwise on the cord take-up device 10, in adiametrically offset orientation. In other words, the aperture 44, forexample, may be located on the cord take-up device 10 at a locationoffset from a point diametrically opposed to a location of the otheraperture 44′.

On dual-purpose shaft 24 is mounted slotted disk 34. Preferably, theaxial surface of dual-purpose shaft first end 38 is an enlarging spiralin the direction of rotation when cable is being added to thedual-purpose shaft 24. This way, the roll-up and roll-down action of thetake-up device is smoothed in the area of radial slot 66 where the firstcomplete wrap of cable encounters the initial layer of cable.

The dual-purpose shaft diameter of dual-purpose shaft 24 is different incompartment 28 and compartment 30. This can be accomplished by use of ahub 35 mounted on dual purpose shaft 24, which results in a largerdiameter surface for cable take-up. The complete tensioning of the flatcoil spring 49 48which is attached to dual-purpose shaft 24 is aphysically limiting factor of the device. Depending on the length of theflat coil spring 48, the spring will allow a certain number ofrevolutions of the dual-purpose shaft 24 as flat wire cable 14 isextended out from the device 10 from compartment 30. It is desired thatwhen this fixed number of revolutions has occurred, and coil spring 48is fully wound, that the appropriate length lengths of cable remain incompartment compartments 28 and 30 around dual-purpose shaft 24. Todetermine the length of cable which should be placed in each ofcompartments 28 and 30, the cord thickness is a variable, as well as thediameter of the dual-purpose shaft 24, and the number of revolutions ofdual-purpose shaft 24 which are allowed by the spring 48. In the bestmode of the invention flat coil spring 48 is 16 feet in length andallows 31 revolutions of dual-purpose shaft 24. Flat wire cable 19 14is0.020 inches in thickness, and the diameter of dual-purpose shaft 24 orhub 35 in compartments 28 (side B) and 30 (side A) varies depending onthe amount of flat wire cable 14 which is to be extended. In a model ofthe device in which 12 feet of flat wire cable 14can extend fromcompartment 28 30, the diameter of dual-purpose shaft 24 or hub35diameter in compartment 30 (side A) is 1.6 inches in diameter . Inthat model, the diameter of dual-purpose shaft 24or hub 35 diameter incompartment 28 (side B) of dual-purpose shaft 24 is 0.250 inches indiameter . In this particular model, compartment 30 (side A) contains 13feet of flat wire cable 19 14and compartment 28 (side B) contains 8 feetof flat wire cable 19 14.

In a model of device 10 from which 24 feet of flat wire cable 14 is tobe extendible from compartment 30 (side A), the diameter of dual-purposeshaft 24 or hub 35 in compartment 30 (side A) is 2.6 inches. Thediameter of dual-purpose shaft 24diameter in compartment 28 (side B) forthis particular model is 0.250 inches. In this model, there are 25 feetof flat wire cable 14 in compartment 30 (side A) and 12 feet of flatwire cable 14 in compartment 28 (side B).

In second compartment 26, the second end 40 of dual purpose dual-purposeshaft 24 has diametric slot 46 for receiving the inside end of coiledflat spring 48. Flat coil spring 48 is received and fixed at its outsideend by spring cup 32 contained within second compartment 26. Spring cup32 is generally cylindrical with an outer cap surface 50 perpendicularto its axis of rotation, cooperating means 52 which are resilient prongson its outer cylindrical surface and spring stop means 54 on its innercylindrical surface. Cup cooperating means 52 is received by andcooperates with second compartment holding means 56 which are notches inthe inner cylindrical wall of the second compartment. In this way,spring cup 32 is held against rotation except to tighten the spring 48,so the dual-purpose shaft 24 is continually under tension to rotate awaysubject to a rotational bias from the spring tension 48and able toretrieve the cable 14into the first take-up compartment 36.

Also, preferably, spring cup outer cap surface 50 has detents 58, 60, 62and 64 to permit engagement therein of a simple spanner type tool endfor initially tightening the flat coil spring 48. This way, our take-updevice may be more easily assembled.

Our take-up device components may be made from plastic or otherpolymeric materials by conventional molding means.

To assemble our invention, first cable 14 is passed through radial slot39 of disk 34 and each end is led out apertures 44 and 44′. On the tipsof each end of the cable is placed a strain relief device 19 and theelectrical connection 12 to attach to the phone and the handset. Then,flat coil spring 48 is engaged on its inside end in diametric slot 46 ofdual-purpose shaft 24, and on its outside end in spring stop means 54 ofspring cup 32, spring stop means 54, and the dual-purpose shaft 24 andspring cup 32 are placed between upper and lower case halves 20 and 22,respectively. Then, the case halves are snapped secured together, anddetents 58, 60, 62 and 64 are engaged, and turned to tighten the flatcoil spring 48 and wind the cable 14 onto dual-purpose shaft 24 incompartments 30 and 28.

While there is shown and described the present preferred embodiment ofthe invention, it is to be distinctly understood that this invention isnot limited thereto but may be variously embodied to practice within thescope of the following claims.

We claim:
 1. A dual reel cord take-up device for flat wire cable whichcomprises: (a) a generally semi-cylindrical upper case half with twoparallel compartments in a direction perpendicular to the an axis of thecylinder upper case half, the a first compartment of said two parallelcompartments being adapted to receive the a first end of a dual-purposeshaft, and the a second compartment of said two parallel compartmentsbeing adapted to receive the a second end of said dual-purpose shaft anda spring cup, said upper case half having snap-fit means for receiving alower case half and means for receiving a flat wire cable; (b) agenerally semi-cylindrical lower case half, also with two compartmentswhich correspond to said first and second compartments of the upper casehalf, said lower case half also having snap-fit means for receiving andcooperating with said upper case half snap-fit means for receiving andfor retaining said upper case half in fixed relationship with said lowercase half, said lower case half also having means for receiving a flatwire cable and said first and second upper half compartments configuredto connect with said lower half compartments to form a first devicecompartment and a second device compartment, said second devicecompartment having holding means for holding said spring cup in saidsecond device compartment against rotation in one direction but not theotherin an opposing direction; (c) asaid dual-purpose shaft supportedand held in rotatable relationship by both the upper and lower casehalveshalf compartments, the dual-purpose shaft being provided on itsfirst end in the first device compartment of the upper and lower casehalves with a slotted disk which divides the first end of thedual-purpose shaft into two adjacent reels for receiving flat wirecable, in which the one of said two adjacent reels are is called a cableextension and take-up reel and another of said two adjacent reels iscalled a captive cable reel; (d) the slotted disk further dividing thefirst compartment into two adjacent compartments, thesaid flat wirecable extendingextends through two apertures within said first devicecompartment one cable end of said flat wire cable fixed in an oneaperture, and the other cable another end of said flat wire cable freeto extend and retract through its a second aperture of said twoapertures, the dual-purpose shaft being provided on its second end inthe second compartment of the upper and lower case halves with a slot inthe dual-purpose shaft for receiving a spring within the spring cup; (e)a generally cylindrical , said spring cup disposed within the saidsecond device compartment of the upper and lower case halves , the saidspring cup having an outer surface perpendicular to its axis ofrotation, ; means cooperating with the holding means of said seconddevice compartment to hold the spring cup against rotation relative tothe upper and lower case halves in said one direction but not in theother an opposing direction, and spring stop means on its an innercylindrical surface of said spring cup for fixing one end of the springto the spring cup; and (f) a flat coil spring disposed within the springcup, the spring being fixed on its outer end to the spring stop means ofthe spring cup and being fixed on its inner end to the slot of thesecond end of the dual-purpose shaft, the flat coil spring being sizedin relation to the a length of the flat wire cable so that when the flatcoil spring is completely wound on the dual purpose shaft, the flat wirecable from on the cable extension and take-up reel still has severalwinds remaining around the dual purpose shaft, and the flat wire cableon the captive cable reel is pressed against the walls of the upper andlower case halves half compartments of the first device compartment, andhas not begun to reverse wind.
 2. The take-up device of claim 1 whereinthe holding means in the second device compartment are comprise notches, which notches configured to cooperate and interact with thecooperating means of the spring cup which are , said cooperating meanscomprising resilient prongs on its an outer cylindrical surface of saidspring cup.
 3. The take-up device of claim 1 wherein the spring cup hasdetent means on its said outer surface thereof perpendicular to its saidaxis of rotation of said spring cup for winding the flat coil spring. 4.The take-up device of claim 1 wherein the two apertures in the lowercase half first device compartment are sufficiently large to permit thepassage of said flat wire cable, but are not large enough to permit thepassage of folded flat wire cable.
 5. The take-up device of claim 1,wherein the dual-purpose shaft has a larger diameter in the cableextension and take-out take-up reel than the a diameter of thedual-purpose shaft in the captive cable reel.